If a foreign national is reporting difficulty getting an EAD in the mail, consider these two common issues.
There must be someone present to receive the EAD. When no one is home, the post office returns the EAD to USCIS. If you are expecting an EAD, make arrangements with your post office to ensure delivery.
If a foreign national moves, you must notify USCIS promptly. Otherwise, the EAD might not be delivered at all. It is not enough to register the address change with the post office. You must do so directly with USCIS.